The Biospecimen Core (Core B) provides part of the infrastructure support for Projects 1 - 4. This Core will provide a well-organized and standardized system of specimen collection, storage, distribution and related clinical/research information dissemination that is based on over two decades of experience. There will be consistency and quality assurance in the pathological analysis of tissue specimens. The Biospecimen Core is also involved in the maintenance of a large series of prostate cancer xenograft lines developed by Core investigators. These xenografts are used for proposed studies by the POI investigators and each study is overseen by Core personnel. Overall, the operations of this Core group into 4 components: 1. Specimen acquisition, processing, quality control, storage and accessioning into databases; 2. A prostate cancer xenograft maintenance, development and study program. 3. Laboratory services, including interpretation of tissues and tissue localization studies by a urologic pathologist, immunohistochemistry (IHC), quantitative RT-PCR, and immunoassays, i.e, PSA, and tissue culture. The Core will also perform pre-clinical studies using our xenograft resources; and 4. An administrative program to obtain samples from minority patients, prioritize the distribution of specimens, conduct a quality control program, and to ensure patient confidentiality and compliance with IRB requirements. The performance of each of the research projects detailed in this program project mandates that investigators have ready access to well documented clinical specimens and relevant biological models. The investigators directing the Biospecimen Core also make it a policy to provide excess prostate cancer specimen resources to POI collaborators and to non-P01 investigators on a world-wide basis. Overall, the Biospecimen Core is a critical component of this P01 program project.